The flow in the Murray in South Australia has risen sharply due to floodwaters from interstate.

SA Water says almost 53,000 megalitres per day are now flowing into SA, a rise of about 10,000 megalitres daily since last Friday.

Some low-lying shack areas are expected to flood by the middle of April, when the flow is forecast to reach about 60,000 megalitres daily.

Russell Peate from the Mid-Murray Council said a close watch was being kept.

"We have weekly meetings, it's really monitoring as to when any actions are required," he said.

"A flow of above 60,000 megalitres does have some inundation potentially of some lower-lying shack sites and it may affect some of the council's lower-lying roads and community waste water management schemes."

High rainfall over recent weeks is being blamed for a rise in mosquito numbers along the Murray, particularly around Renmark and Murray Bridge.

University of South Australia researcher Stephen Fricker says, despite the increase, numbers are much lower than last year.